Marking pen



FIG. 1 is a top perspective view of a marking pen showing my new design;

FIG. 2 is a top perspective view in an exploded condition;

FIG. 3 is a side elevational view;

FIG. 4 is a top plan view; and,

FIG. 5 is a bottom plan view. 

The ornamental design for a marking pen, as shown. 